1. Field of the Invention
The present invention relates to a control apparatus and a signal analyzing system; particularly to a control apparatus and a signal analyzing system on which software with reduced data transfer load capability operates.
2. Description of the Related Art
FIG. 10 shows a conventional control apparatus using a semiconductor manufacturing apparatus as an example. In FIG. 10, numeral 1 denotes a control apparatus using a semiconductor manufacturing apparatus as an example; the control apparatus comprises a signal input means 2 such as a sensor and a measuring instrument detecting/measuring a pressure, a temperature, etc. inside the control apparatus, an analog-digital signal converter 3 for quantifying an analog signal inputted, control software 4 for calculating control result from the input signal quantified, and a control means 5 actually performing control based on control result. Numeral 6 denotes a conventional input signal analyzing system, and numeral 7 denotes analyzing software which operates within the input signal analyzing system 6.
In the field of semiconductor manufacturing, there are needs for analyzing a signal inputted from the signal input means 2 such as sensors or measuring instruments, for the purposes of maintenance or failure analysis in addition to its intended purpose which is control by a control means.
For this reason, there is a method for connecting each sensor or measuring instrument 2 to an analyzer such as an X-Y recorder by direct wiring. However, this method has problems in that wiring becomes cumbersome and time required for wiring increases, as the number of sensors or measuring instruments needed to be analyzed increases.
As a method for solving these problems, there is a system called “Manufacturing Execution System (MES)” if a control apparatus 1 shown in FIG. 10 is a semiconductor manufacturing apparatus. Using this system, a signal inputted to multiple sensors or measuring instruments can be transferred to the outside of the control apparatus by only one communication cable in a software-like manner. The MES is an analyzing system shown as numeral 6 in FIG. 10, and it is a worldwide-known standard system as a system attached to a semiconductor manufacturing apparatus.
When the MES is used, a signal inputted from a signal input means 2 such as a sensor and a measuring instrument is converted to numerical data by an analog-digital signal converter 3, is temporarily placed in a data area in control software 4, is data-converted by a conversion driver included in the control software 4, and is transferred to analyzing software 7 operating on the analyzing system 6.
As a widely prevalent system, the MES has many features and the following characteristics:
This data transfer system is a robust system that it always sends back an acknowledgement to every received outgoing message.
Its message data structure is built using a list structure, and a communication interface or a conversion driver for analyzing the list structure is always required on the message-sending side and on the message-receiving side.
Because the MES 6 has the characteristics described above, it has the following problem: If it is used for signal analysis of the signal input means 2 such as a sensor or a measuring instrument, load on the conversion driver increases as data volume increases, which exerts an influence on operations of the control software 4 and the analyzing system 6; if things come to the worst, the control apparatus or the signal analyzing system is halted.